Run Distribution Over Flattened Partitions
Olivia Nabawanda
Department of Mathematics
Makerere University
P. O. Box 7062
Kampala
Uganda
Fanja Rakotondrajao
Département de Mathématiques et Informatique
Université d'Antananarivo
Antananarivo
Madagascar
Alex Samuel Bamunoba
Department of Mathematics
Makerere University
P. O. Box 7062
Kampala
Uganda
Abstract:
The study of flattened partitions is an active area of current
research. In this paper, our study unexpectedly leads us to the OEIS
sequence A124324. We provide a new combinatorial interpretation of these
numbers. A combinatorial bijection between flattened partitions
over [n + 1] and the partitions of [n] is
also given in a separate section. We introduce the numbers
fn,k, which count the number of flattened
partitions over [n] having k runs. We give recurrence
relations defining them, as well as their exponential generating function
in differential form. It should be appreciated if its closed form is
established. We extend the results to flattened partitions where the
first s integers belong to different runs. Combinatorial proofs
are given.
Full version: pdf,
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(Concerned with sequences
A002182
A004394
A040047
A323256
A323257.)
Received February 10 2020;
revised versions received July 1 2020; August 5 2020; October 15 2020.
Published in Journal of Integer Sequences, October 15 2020.
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